Hydraulic tappet



Feb. 4, 1958 Filed June 1, 1955 G. D. LINE HYDRAULIC TAPPET 2 Sheets-Sheet l i I F 22 A 4&0

T i 26 4o Fig.2

INVENTORI GERALD D. LINE ATTORNEYS Feb. 4, 1958 ca. D. LINE HYDRAULICTAPPET 2 Sheets-Sheet 2 Filed June I 1954 wsw ' mmvrm GERALD 0. LINEATTORNEYS United States Patent HYDRAULIC TAPPET Gerald 1). Line, RoyalOak, Mich., assignor to Eaton Manufacturing Company, Cleveland, 01110, acorporation of Ohio Application June 1, 1954, Serial No. 433,572

19 Claims. (Cl. 123-90) This invention relates to tappets and moreparticularly to hydraulic tappets for internal combustion engines.

Broadly the invention comprehends the provision of a hydraulic tappet orlitter of the full hydraulic fluid registration type, for use in a valvegear system of internal combustion engines, which incorporates structurefor minimizing hydraulic fluid drainage from the tappet during periodswhen the engine incorporating said tappet is shutdown, for providing awiping of varnish deposits from the cooperative surfaces of the body andplunger of the tappet and for providing a maximum available supply offluid in the plunger.

Full hydraulic fluid registration type hydraulic tappets heretoforedevised have had shortcomings in the structure thereof due in part tothe fact that because of the particular arrangement of fluid flowcommunication therethrough, from a source of fluid under pressure, alimited fluid supply is provided in the plunger and a ready drainage ofthe fluid from said tappet is possible when an engine, incorporatingsaid tappet, is shutdown. Drainage results in noisy starts of the enginewhen it is again placed in operation after a period when it is shutdown.The presently devised tappet, through the provision of preferably anarrow angular or elliptical annular groove, that is a groove ofsubstantially uniform channel width having an axial extent ofcommunication much greater than its channel width, as part of theplunger or cylinder body construction for the tappet together withappropriate ports in the plunger and body, has materially improved theoperating characteristics of tappets of the full hydraulic fluidregistration type particularly as relates to drainage and plunger fluidsupply.

Among the principal objects of the invention is the provision of ahydraulic tappet of the full fluid registration type, having a narrowelliptical groove on either the external surface of the plunger orinternal surface of the body thereof, that;

a. Is of simple and economical construction;

b. Eliminates the necessity of providing cooperating annular grooves onthe body and plunger of the tappet;

c. Because of the high and low points of the grooves and with rotationbetween the plunger and body a wiping free of varnish deposits from thecooperating surfaces of the body and plunger is achieved;

d. Will shear oif varnish deposits, when the plunger bottoms in thebody, even though rotation does'not occur during a condition ofshutdown;

e. Permits of the placing of the fluid cooperation port in the plungerat the high point therein thus increasing the available supply of fluidin the plunger;

Provides for the communication of supply fluid to the plunger for tappetoperation and to the socket of the tappet for subsequent supply to themechanism of the valve gear system; and,

g. Provides for communication thereof with appropriate ports in theplunger and body for all operativepositions 2,821,970 l atented Feb. 4,1958 of relative angular and axial movement between the plunger andbody.

Other objects and advantages of the invention will appear from thefollowing description taken in connection with the drawings forming apart of the specification, and in which:

Fig. 1 is a vertical cross-sectional partly broken away view of ahydraulic tappet, embodying the invention;

Fig. 2 is a cross-sectional view taken substantially along lines 22 ofFig. 1;

Fig. 3 is a perspective partly broken away view of the plunger of thetappet shown by Fig. 1;

Fig. 4 is a vertical cross-sectional partly broken away view of amodified form of tappet embodying the basic invention disclosed by Figs.1 through 3;

Fig. 5 is a vertical cross-sectional partly broken away view of afurther modified form of tappet embodying the basic invention hereof;and,

Fig. 6 is a perspective partly broken away view of the plunger of Fig.5.

This invention was devised primarily for the purpose of providing anovel fluid flow communication construction through the body and plungerof an internal combustion engine hydraulic tappet of the full fluidregistration type such as to minimize drainage of the fluid from thetappet when the engine in which employed is shutdown. By the provisionof preferably a narrow elliptical groove, that is all positions ofrelative angular movement between the tappet, plunger and body andlimited relative axial movement therebetween, is confined to a narrowpassageway and at the highest point possible so as to increase anavailable fluid supply in the plunger. The form of grooving hereinprovided additionally is very effective to remove varnish deposits whichmight occur upon the cooperating surfaces of the body and plunger.

The provision of an annular groove as herein devised permits of a simplearrangement for the supplying of fluid through the plunger to a push rodand overhead valve operating mechanism adapted to be operativelyassociated with the tappet. This is possible by communicating with theelliptical groove at a point remote from the communication through theplunger with the interior of the tappet.

Referring to the drawings for more specific details of the invention 10represents a hydraulic tappet for incorporation in a valve gear systemfor internal combustion engines between a cam, not shown, and pushrod,not shown.

The tappet 10 comprises basically a hollow cylindrical body 12 closed atone end 14, a plunger 16 reciprocable in the hollow of the body, a flatcheck valve 18 supported for engagement with one end of the plunger anda spring 20, arranged in the hollow of the body, axially biasing theplunger outwardly thereof.

A spring clip 22 is appropriately held in an annular groove 24, on theinternal peripheral wall of the body 12, for limiting the outward axialmovement of the plunger whereas a shoulder 26 formed on the internalperiphery of the body is adapted to be engaged by a shoulder 27 on theexternal periphery of the plunger to limit its opposite axial extent ofmovement relative to the body.

The plunger 16 consists of two parts, a sleeve member 28 and a capmember 30 appropriately arranged on one end 32 of the sleeve andproviding a reservoir or low pressure chamber 34 internallytherebetween.

The end 36 of the sleeve opposite end 32 thereof provides a fluid portor passage 38, communicating with chamber 34 and a high pressure chamber40 provided between the end, 36 of sleeve member 28 and the closed end14 of the body, adapted to be controlled by flat check valve 18. Acombination cage and valve spring structure, 39 fixedly mounted on areduced extension 42 of plunger 16 serves to confine the movementofvalve 18 therein as well as normally hold said valve on its. seat onthe plunger to control port 38. Spring portion 43 of structure 39 isstamped therefrom of spiral form and thus provides openings through thestructure to permit communication therethrough with the chamber 40.

Fluid reservoir 34 provided centrally of sleeve member 28 hascommunication exteriorly thereof by way of port 38 at. end 32 thereofand a. port 44 provided in the wall thereof. Port 44 is the means bywhich hydraulic fluid is supplied to the tappet for the operationthereof wherein a relatively narrow, elliptical or angular annular,groove 46, on the outer periphery of the sleeve, is connected therewith.Groove 46, as noted from Figs. 1 through 3 of the drawings, liesangularly to a plane arranged perpendicular to the axis of the tappetwith its furthest remote, axial limits, that is points A and B beingsubstantially circumferentially 180 apart on the.

outer periphery of the plunger, the purpose of which will hereinafterappear.

A pair of diametrically opposite ports 48 arranged in the wall of body12 provide communication between the groove 46 and an annular groove 50arranged on the outer peripheral surface of the body whereby ashydraulic fluid is supplied to groove 50 it can pass in a continuouspath through ports 48, groove 46 and port 44 to reservoir 34.

By reason of the provision of groove 46 a confined continuous path orpassage for hydraulic fluid is maintained between ports 48 in body 12and port 44 in plunger 16 for all limits of relative axial and angularmovement between the plunger and body. Furthermore because of theangular disposition of groove 46 on the plunger, port 44 is arranged atapproximately the highest point of communication possible between theexterior of the plunger and the chamber 34 thus providing a maximumfluid. supply in the plunger chamber 34. With the provision of solelyone port 44 in plunger 16 communicating by way of the narrow channelconfines of groove 46 with port 48 a minimizing of the drainage of thefluid from the tappet is possible under shutdown conditions of an enginein which employed, thereby minimizing the possibility of noisy startswhen said engine is placed back in operation.

Due to the wide axial zone covered by groove 46, rotation which normallyoccurs in operation between the plunger and the body serves to wipe freevarnish deposits which might accumulate on the interior surface of body12. Furthermore, because of the narrowness of groove 46, even though norotation occurs between the plunger andbody during periods of engineshutdown, the plunger will bottom and serve to shear off varnishdepositsfrom the body.

Plunger 16. is bottomed as shown in Figs. 1 and2 when shoulder 27 of theplunger axially abuts shoulder 26 provided on the interior of the bodyadjacent an annular groove 52 provided therein.

Itwill be quite obvious in viewing Figs. 1 through 3 that groove 46could be equally as well applied to the internal surface of body 12instead of the external surface of plunger 16 and serve a like eflicientpurpose.

Fig. 4 illustrates a modified form of tappet fromthat shown in Figs. 1and 2 wherein a plunger 16 is provided on its external surface with apair of criss-crossed communicating grooves 46 with the provision of aport 44 through the wall of the plunger at one crossing point of, thegrooves 46 Grooves 46 are provided communication to. the exterior of,thetappet by way of'a single 4 port 48 provided through the wall of body12 Grooves 46 port 44 and port 48 serve a like purpose as the comparablestructure of Figs. 1 and 2.

Fig. 5 illustrates a modified form of tappet 10 from that of Figs. 1 and2 wherein plunger 16 includes a sleeve member 28 and a cap member 30 Capmember 30 includes a socket 54 adapted to receive a push rod, not shown,therein, intercommunicating passages 56 and 58 providing communicationpassageway between socket 54 and an annular groove 60 arranged in theexternal' surface of cap member 30 Groove 60 is in turn in communicationwith a port 62 provided in the wall of plunger 16. and port 62 is inturn in communication with an elliptical groove 46 provided on theexternal surface of plunger 16". Groove 46 communicates with a chamber34 centrally of the plunger by way of a port 44 and exteriorly of thetappet by way of ports 48. in the wall of body 12 Groove 46 in additionto serving the purpose of providing fluid communication to chamber 34from an external pressure source, not shown, byway of port 44 providesfluid communication to'socket 54 by way of port 62, groove 60, passage58 and passage 56. It is through the angular disposition of groove 46 onthe plunger surface that is possible for it to'serve a dual fluid supplycommunication to socket 54 and chamber 34 thus eliminating the necessityof an additional groove as is conventionally required.

Likewise as in the structure of Figs. 1 and 2, groove 46 could equallyas well be arranged on the internal surface of body 12 instead of on theexternal surface of plunger 16 Although the grooves 46, 46 and 46 aredisclosed in the specific form of elliptical or angular grooves, it isreadily conceivable that numerous modifications thereof could be devisedto serve an identical purpose. Accordingly, it is the basic concepthereof, as expressed by the appended claims, that the grooves be ofsubstantially uniform channel width and be so arranged on the plunger orbody of such cooperating mechanism as to provide for communicationtherewith over an axial distance appreciably greater in dimension thanthe channel width of the groove.

What I claim is:

1. A hydraulic tappet comprising a hollow body having an-open end and aclosed end, and a plunger reciprocable in said body and providing athrust transmitting fluid chamber between one end thereof and the closedend of said body, said plunger and body having an annular groove, ofsubstantially uniform width, between cooperating peripheral surfacesthereof extending over an axial extent of said plunger greater than thewidth of the groove, said plunger and body having several ports in thecooperating wall surfaces thereof registrable with the groove providingfor continuous communication between the chamber and the exterior ofsaid body through the ports and groove-for predetermined limitedrelative axial movement and for all positions of relative angularmovement between said plunger and body.

2. A thrust transmitting mechanism comprising a hollow cylinder memberhaving an open end and a closed end, and a plunger member reciprocablein said hollow member and providing therebetween with said hollow membera thrust transmitting fluid chamber, one of said members having anannular groove in a peripheral wall surface thereof, cooperating with aperipheral wall surface of the other member, said groove having anannular portion thereof disposed axially closer to one axial end of saidmember, in which arranged, than another annular portion thereofcircumferentially spaced therefrom, said members having ports throughthe walls thereof registrable with the, groove, providing, with thegroove, continuous communication between the chamber and the exterior ofthe body irrespective of relative angular and limited axial movementbetween the plunger and body.

3, A tappet according to claim 1 wherein means are provided for limitingrelative axial movement between said plunger and body.

4. A tappet according to claim 3 wherein the axial distance between oneaxial end limit of the groove and the opposite axial end limit of thegroove is greater than the limited relative axial movement between saidbody and plunger.

5. A tappet according to claim 1 wherein the groove is substantiallyelliptical.

6. A tappet according to claim 1 wherein the groove lies substantiallyin a plane ofiset angularly to a plane perpendicular to the axis of saidplunger and body.

7. A tappct according to claim 1 wherein the groove is arranged in theexternal peripheral surface of said plunger, and wherein the portsinclude one port in said plunger registrable with the groove and a pairof circumferentially spaced ports in said body registrable with thegroove.

8. A tappet according to claim 7 wherein the axis of the ports in saidbody be substantially in a plane perpendicular to the axis of said bodyand circumferentially spaced substantially diametrically opposite oneanother and wherein the opposite axial extremities of the groove arecircumferentially spaced substantially 180 apart.

9. A mechanism according to claim 8 wherein the groove is ofsubstantially uniform width throughout its annulus and liessubstantially uniformly angularly to a plane perpendicular to the axisof said body and plunger, wherein the groove is arranged on the externalperipheral surface of the plunger and wherein the ports comprise, a portin said plunger registrable with the groove and having communicationwith the chamber and a pair of diametrically opposite ports through thewall of said body registrable with the groove and adapted to havecommunication with a supply of fluid externally of said body.

10. A mechanism according to claim 2 wherein means are provided forlimiting the relative axial movement between said plunger and body, andwherein said annular portions of the groove are axially spaced apart adistance substantially equal to the limit of relative axial movementbetween said plunger and body and circumferentially spaced apartsubstantially 180, such as to provide continuous communication betweenthe ports and groove for all positions of relative axial and rotativemovement between said plunger and body.

11. A thrust transmitting mechanism comprising a hollow body having anopen end, and a plunger reciprocable in said body and providingtherebetween with said body a thrust transmitting fluid chamber, saidplunger and body having a continuous circumferential substantiallyuniform width groove arranged between cooperating peripheral surfacesthereof with one axial extremity of the groove being axially spaced toone side of a plane perpendicular to the axis of said plunger and bodyand an opposite axial extremity of the groove being axially spaced tothe opposite side of the plane from the first axial extremity of thegroove by a distance greater than the width of the groove, said axialextremities of the groove being circumferentially spaced substantiallyfrom one another, and said plunger and body having a combined pluralityof ports in their peripheral surfaces registrable with the groove.

12. A mechanism according to claim 11 wherein means are provided forlimiting the relative axial movement between said plunger and body, andwherein the groove has communication with the ports for all positions ofrelative axial and rotative movement between said plunger and body.

13. A mechanism according to claim 12 wherein the groove is arranged inthe external peripheral surface of said plunger angularly uniformlydisposed to a plane perpendicular to the axis of said plunger, andwherein one of the ports is in said plunger registrable with the groove.

14. A mechanism according to claim 13 wherein a pair of the ports are insaid body diametrically opposite one another and registrable with thegroove.

15. A mechanism according to claim 13 wherein a second continuouscircumferential groove is provided in the external peripheral surface ofsaid plunger arranged in angular crossing relation and communication tothe first groove and of substantially like angular disposition as thefirst groove.

16. A mechanism according to claim 13 wherein said plunger haspassageway means therein registrable with the groove and providingcommunication between an end of said plunger opposite from the thrusttransmitting chamber end thereof and the groove.

17. A mechanism according to claim 16 wherein said plunger includes asocket member secured in one end thereof having the passageway meanstherethrough, and wherein another port is provided in the plungerproviding communication between the groove and the passageway means.

18. A mechanism according to claim 17 wherein a pair of the ports arearranged diametrically opposite one another in the body registrable withthe groove.

19. A mechanism according to claim 15 wherein said body has a porttherein registrable with one of the grooves.

References Cited in the file of this patent UNITED STATES PATENTS1,482,478 Milligan Feb. 5, 1924 1,492,917 Bruegger May 6, 1924 1,499,290Casey June 24, 1924 1,528,817 Dinnes Mar. 10, 1925 1,726,259 DaisleyAug. 27, 1929 2,595,583 Johnson May 6, 1952

